Any pics of your setup Lseries with Dual sidedrafts and using a regulator and fuel return line

[benzo]

Hello

 

Would any of you running an Lseries with dual sidedrafts have pics of how you've run the fuel pressure regulator and return line? Thanks @datzenmike for your feedback.

 

I am trying to eliminate vapor lock and my current setup the fuel line dead ends at the carb. Was thinking of getting a T banjo fitting and connect a line to a regulator and then line to the fuel return but wanted some confirmation from others that have done this and how they routed it.

 

Also have any of you used this filter? I was thinking of replacing my stock filter location with this in between the feed and the pump and then run a line from this to the return 

 

Thank you

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Edited May 27 by benzo

[banzai510(hainz)]

My 510s I never used a return line.

 

MY yellow car had 44s and a cheap dial pulatator regulator that the orginal owner used for 30yrs with a mallory fuel pump. I assume a low pressure pump.

 

My beater Banzai 510 with 40mm has nor reg and not return. Just a stock mechanical fuel pump.

 

 

I guess you want to run a return.

[benzo]

@banzai510(hainz) It seems I have a return line already( line by the feed line for the fuel filter ) just need to connect to it.  Recently got stuck in traffic and felt vapor lock happen. Luckily I was able to get past it but want to try to eliminate it in case I run into another traffic issue. At first I was going to just pull over and chill and wait til traffic moves and start back up. I want to see what others have done to see if it lines up with my minds eye on how to run a regulator to return line or if someone has tried the filter I had mentioned.

 

 

Edited May 27 by benzo

[banzai510(hainz)]

I dont have vapor lock but I dont drive in traffic if over 85deg in town. If Im rolling I think Im fine with the 3 core rad. doing at least 35mph.

 

I will not drive in town stop and go its too much.

 

if you go a elelctric pump will be better for your situation I think.

I notice on the mechanical pump once the carbs are full  the arm goes limp. so it not using the whole diaphrame in full movement. Now if you have full movement I think the diaphrame will wear out faster. then they tear and gas goes in oil pan(this is just my opinion here)

 

 

[benzo]

@banzai510(hainz) Yeah I don't normally drive in traffic but this one time I go for a drive a major accident happened causing traffic or inching along so want to remedy this for future possible situations. 

 

I have heard that too about the pump. That is something on my mind of options. Was looking at adding a pump by the tank. 

[datzenmike]

Describe what you call vapor lock. It's not hot enough in SF yet. Under hood temperatures have to be high enough to boil gasoline.

[benzo]

@datzenmike the coolant temp didn't get high, but I was sitting in traffic for a while. It was a nice day but not super warm or hot. The engine idle started to drop and it was running a little rough or like a miss, so I got onto the shoulder and drove for a bit, and the car started to drive like normal again. I had to get back onto the road as traffic was funneling so it started to have symptoms again so I would feather the gas pedal but did let it idle to see if would die out and it did but luckily it started back up and I just feathered the gas pedal to keep fuel flowing and once I got onto open road and moving the car drove like normal and things cooled off. It used to be worse, but I had insulated the fuel lines and added a heat shield extension which helped but hasn't fully cured the vapor lock.

[Crashtd420]

16 hours ago, benzo said:

@banzai510(hainz) It seems I have a return line already( line by the feed line for the fuel filter ) just need to connect to it.  Recently got stuck in traffic and felt vapor lock happen. Luckily I was able to get past it but want to try to eliminate it in case I run into another traffic issue. At first I was going to just pull over and chill and wait til traffic moves and start back up. I want to see what others have done to see if it lines up with my minds eye on how to run a regulator to return line or if someone has tried the filter I had mentioned.

 

 

This is my opinion,  keep it simple...

Don't worry about a regulator, place a tee just before the carburetor fuel inlet, then connect to a return....

Make sure it is a return line...

On my 521 I sent my return line into the vent line of the tank then added a vent off the filler neck....

Next temporarily add a fuel pressure gauge after the tee at the carburetor inlet and see what the pressure is... if your return line doesn't have any sort of restriction which it should,  then you need to create one so the fuel doesn't just flow to the tank.... for that i simply used a spare air corrector jet and installed it inside the rubber line connecting the tee to the return... I was able to fine tune the pressure at the carburetor by changing that air corrector size on the return.... 

Last thing is remove the fuel gauge, I left one there and it started to leak from the exhaust heat... not good....

[datzenmike]

Even better is the 'fuel rail' from an L20B. Everything needed is there including the pin hole restriction.

 

 

I wouldn't use the tank vent as a return. Too much could go wrong but it can be done. Tank has to be vented. 

[benzo]

@Crashtd420 Thanks for your thoughts. @datzenmike Thanks for the post of the pic of the L20 fuel line.

[demo243]

I’m not running a return on my PHH carbs on my 510, but I am on my HSR set up on the Z. I wanted to run a return on the HSRs since they are VERY pressure sensitive, and will just puke fuel out the vents if over pressurized.
 

I am running a Carter low pressure electric pump if that makes a difference. And I did run new fuel and return lines to an aftermarket tank. So definitely a few differences. 

I had a hard time finding a post fuel rail/carb pressure regulator that didn’t require a massive fuel return line. I ended up using a Holley low pressure regulator ahead of the rail and carbs and then running a restrictor on the return line to keep pressure. Not exactly how the regulator is designed to work- but seems to be working for me.

 

Heres the break down-

 

Tank -> 5/16” soft line -> Carter pump -> 5/16” soft/hard/soft line -> Fuel Rail (carbs feed from rail) -> 1/4” soft line   -> Restrictor -> 1/4” soft/hard/soft line -> Tank

 

I ran a pressure gauge at the end of the fuel rail post carbs to confirm pressure and it seems to hold fine. At some point I’d like to add one in the car but haven’t done it yet. 
 

The return definitely keeps the fuel noticeably cooler. When running the engine, manifold and carbs will be warm but the rail itself will be cold.

 I did have to move my fuel rail mounts from the manifold to the carb body. I noticed that even with a heat shield once I shut off the car the residual heat from the engine would heat the manifold and then the rail. Once I moved the mounts to the isolated carb bodies (which are also protected by a heat shield) the rail stayed much cooler.

 

Heres a quick photo - I’ve since moved the regulator to the firewall, but the progression/setup remains the same.

 

I am running the Carter P4070 from Summit I think.

 

Holley 12-804 Low pressure regulator, from Summit.

In line fuel restrictor I picked it up from Showtime Freestyle (a jet ski place…) it lets you run a Mikuni jet on the end to adjust the back pressure if needed, fits 1/4” fuel line.  They don’t seem to have the aluminum one Im running now but Atlantic Jet Sports does - https://www.atlanticjetsports.com/products/riva-fuel-line-return-restrictor?srsltid=AfmBOoqHIMBBeV-eSX2euKVKMk9Nl2VwYUWK6ZedvzwTzCDf99dKmf7I

 

I’m currently thinking about building another HSR set up for my 510 and if I do will run the same set up. Even if I don’t go HSR carbs on the 510 I still want to do this for the PHH carbs anyway…. Just need the time to get to it…

Edited May 28 by demo243

[banzai510(hainz)]

Benzo

My 40s when it loads up sometimes I open the top and my jet Block is backed out.

always ck that also.  for soem reason mine always backs out. on both carbs.

[benzo]

@demo243 Thanks for the info and pic. I remember your Z setup. Cool stuff!

 

@banzai510(hainz) Yeah I always check those as one time it did back out on me making it feel like vapor lock. Thanks!